Final answer:
The steering and sailing rules for vessels in restricted visibility apply to vessels navigating in or near an area of restricted visibility, regardless of whether they have special purpose lights or operational radar.
Step-by-step explanation:
In restricted visibility, the steering and sailing rules apply to vessels that are navigating in or near an area of restricted visibility, regardless of whether they are showing special purpose lights or have operational radar. So option 3, navigating in or near an area of restricted visibility, is the correct answer. In fog or other conditions of restricted visibility, these rules help vessels avoid collisions and ensure safe navigation.